An Etymological Dictionary of the German Language/zeigen
zeigen, ‘to show, point out, demonstrate,’ from MidHG. zeigen, OHG. zeigôn, str. vb., ‘to show, indicate’; a specifically HG. derivative of the Teut. str. verbal root tī̆h, ModHG. zeihen. The latter comes from MidHG. zîhen, str. vb., ‘to accuse of, depose concerning,’ OHG. zîhan, ‘to accuse'; also ModHG. verzeihen, ‘to pardon,’ MidHG. verzîhen, OHG. frizîhan, ‘to deny, refuse pardon.’ Based on the Aryan str. verbal root dik (for dig see Zeichen); comp. Sans. diç, ‘to exhibit, produce, direct to,’ Gr. δείκνυμι, ‘to show,’ Lat. dico, ‘to say.’ The primary meaning of the root is preserved by Zeichen and zeigen, as well as by Goth. gateihan, ‘to announce, narrate, proclaim, say’; comp. the compounds OSax. aftîhan, AS. ofteón, ‘to deny.’ In HG. the word seems to have acquired a legal sense (comp. Lat. causidicus judex); comp. Inzicht.